1. Field of the Invention
The present invention relates to a skew adjusting apparatus for an optical disc player, and more specifically to a skew adjusting apparatus for making an adjustment of a positional relationship between a disc and an optical axis of an objective lens of a pickup.
2. Description of the Related Art
When a disc from which information can be read by an optical disc player is a medium such as a DVD (digital video disc) having fine pits, a permissible range of a positional relationship between the surface of the disc and the optical axis of the objective lens of the pickup of the optical disc player becomes narrow. As a result, in the manufacturing process of DVD players or the like, it is required to carry out a skew adjustment treatment of making a fine positional adjustment of a guide shaft after mounting the guide shaft and the other components on the chassis or making a fine positional adjustment of a turntable for the disc. For example, a fine adjustment of the guide shaft can be carried out by moving the end of the guide shaft in the direction of the optical axis of the objective lens of the pickup so that the optical axis of the objective lens becomes perpendicular to the surface of the disc.
There has conventionally been known a skew adjusting apparatus described in Japanese Patent Application No. H10-222,009, in which a positional adjustment of an optical axis was made by moving a guide shaft of a carriage during manufacturing optical disc players. In such an apparatus, the end of the guide shaft is held in the vertical direction between the lower end of a compression coil spring mounted on a bracket fixed on the chassis and the front end of an adjusting screw screwed on the chassis, and the end of the guide shaft is supported in a longitudinal groove of the bearing mounted on the chassis so as to be movable up and down. The turning operation of the adjusting screw to move it in the thickness direction (i.e., in the vertical direction) of the chassis thereon causes the end of the guide shaft to move in the vertical direction on the chassis, thus making a skew adjustment.
However, in the conventional skew adjusting apparatus, the adjusting screw, the bearing, the compression coil spring and the bracket are disposed so as to be placed one upon another in the direction of the optical axis of the objective lens, i.e., in the thickness direction of the chassis, resulting in increased thickness of the optical disc player. Especially, in case of the portable player, such a structure makes it hard to decrease the thickness of the player, thus causing a problem.
An object of the present invention is therefore to provide a skew adjusting apparatus for an optical disc player, which permits to decrease the thickness of the optical disc player.
In order to attain the aforementioned object, the skew adjusting apparatus of the present invention, for making a positional adjustment of a guide member of a carriage for a pickup relative to a chassis has the following features:
a movable body is disposed on said chassis, said movable body having at one end thereof a supporting member for said guide member and at another end thereof a connection member to said chassis; and
an adjusting device for making a positional adjustment of said guide member through said supporting member in a thickness direction of said chassis is disposed between said chassis and said movable body so as to be displaced from said guide member and said supporting member on a reference plane of said chassis.
The connection member of said movable body may pivotably be connected to said chassis through a pivot shaft that is in parallel with said reference plane so that the positional adjustment of said guide member can be made by swinging said movable body around said pivot shaft by means of said adjusting device.
The movable body may have flexibility so that the positional adjustment of said guide member can be made by bending said movable body by means of said adjusting device.
The guide member may comprise a screw shaft for transmitting a driving force to said carriage; and the supporting member of said movable body may comprise a bearing for said screw shaft.
The screw shaft may be connected to an output shaft of a motor through a gear train; and the gear train may comprise a drive gear fixed to said output shaft, a driven gear fixed to said screw shaft and an intermediate gear engaging with said drive gear and said driven gear, said intermediate gear being movable along an arc having a central point, which is identical to a central axis of said pivot shaft.